Cover for a faucet mixing valve



FIG. 1 is a perspective view of a cover for a faucet mixing valve showing my new design;

FIG. 2 is a side elevational view thereof, the left, right, front and rear sides being mirror images of one another;

FIG. 3 is a bottom plan view thereof; and,

FIG. 4 is a top plan view thereof.

The broken line showing is for illustrative purposes only and forms no part of the claimed design. 

The ornamental design for a cover for a faucet mixing valve, as shown and described. 